Objective Chitosan nanoparticle (nanochitosan) has a broad antimicrobial spectrum against diverse pathogenic microorganisms. However, its effect on dental caries-associated microorganisms, such as Streptococcus mutans and Candida albicans is yet to be explored. These microorganisms are known for causing early childhood caries. Therefore, this study was aimed at investigating nanochitosan inhibition capacity against dual-species biofilms of S. mutans and C. albicans. In this study, nanochitosan antimicrobial activity is reported against mono and dual biofilm species of S. mutans and/or C. albicans at 3 and 18 h incubation time. Nanochitosan inhibition capacity was observed through biofilm mass quantity and cell viability. Results The present study successfully synthesized nanochitosan with average diameter of approximately 20–30 nm, and also established dual-species biofilms of S. mutans and C. albicans in vitro. With nanochitosan treatment, the cell viability of both microorganisms significantly decreased with the increasing concentration of nanochitosan. There was no significant decrease in biofilm mass both in the dual and single-species biofilms after 3 h of incubation. However, greater inhibition of biofilm was observed at 18 h incubation.

Highlights Chitosan hybridized with titanium dioxide nanoparticles improves its bone regeneration capability. Nano titanium dioxide addition to the matrix of chitosan sponges was done successfully, as depicted from an even distribution of nano titanium dioxide on the surface of the sponges. Chitosan – nanoTiO 2 scaffold results in significantly improved sponge robustness, biomineralization, and bone regeneration capability, as indicated by DMP1 and OCN gene upregulation in chitosan-50% nanoTiO 2 sample.

The aim of this study is to examine the effect of nano hydroxyapatite in the toothpaste and its effect on the pH and microbial activity. Nano-hydroxyapatite (nHAp) is considered one of the materials that have high biocompatibility for biomimetic material due to its chemical and morphological similarity with dental apatite. Additionally, it has been documented to possess antibacterial potentials. The present study was conducted to identify the relationship between oral microenvironment pH change and its role in the Streptococcus mutans viability, a common pathogen in the oral cavity. Change in pH is closely related to number of Streptococcus mutans as the main cariogenic organism and acid-producing bacteria. The study was carried out using 0.25%, 0.7%, and 1.5% concentration of HAp in toothpaste formulation and commercial toothpaste as control. Our studies showed that the most significant pH fall was observed in 1.5% and 0.7% nHAp. However, in 60 minutes, all nHAp groups were able to restore pH into neutral, especially in the 0.7% nHAp, which reached a pH of 7. As a comparison, the commercial toothpaste only returned to 6 within 1 hour. Experimental method of this study is In vitro oral microenvironment pH and microbiological analysis on teeth fragment. The detailed data about microstructure and antibacterial activity will be presented.